Fluid pressure reduction device

Abstract

A multi-plate, anti-cavitation fluid pressure reduction device includes a stack of annular plates having a hollow center, a fluid inlet at an inner perimeter thereof and a fluid outlet at an outer perimeter thereof. Selected ones of the plates each define at least one pressure reduction stage including an orifice having a well-rounded or well-tapered inlet and an abrupt discharge, and a communication passage coupled to the discharge. Each pressure reduction stage communicates with another pressure reduction stage in an adjacent one of the annular plates in the stack. Two or more pressure reduction stages are coupled in series to define a pressure reduction flow path from the fluid inlet to the fluid outlet. Each pressure reduction stage is preferably characterized by a velocity head loss greater than 75% and a corresponding pressure recovery less than 25%. The fluid pressure reduction device is typically incorporated into a fluid control valve.

What is claimed is:  
     
       1. A fluid pressure reduction device comprising: 
       a stack of annular plates having a hollow center, a fluid inlet at a first perimeter thereof and a fluid outlet at a second perimeter thereof;  
       selected ones of said plates each defining at least one pressure reduction stage comprising an orifice having a well-rounded or well-tapered inlet and an abrupt discharge, said orifice having walls which do not diverge in a downstream direction between said inlet and said abrupt discharge, and a communication passage coupled to said discharge; and  
       each pressure reduction stage communicating with another pressure reduction stage in an adjacent one of the annular plates in said stack, two or more of said pressure reduction stages being coupled in series to define a pressure reduction flow path from said fluid inlet to said fluid outlet.  
     
     
       2. A fluid pressure reduction device as defined in claim  1  for use with a movable plug engaged within the hollow center, wherein said annular plates define at least one axial flow path through said stack for gradual reduction of fluid pressure at different axial levels in said stack of annular plates. 
     
     
       3. A fluid pressure reduction device as defined in claim  2  wherein said axial flow path opens onto the hollow center of said stack of annular plates for gradual reduction of fluid pressure between said annular plates and said movable plug at different axial levels in said stack of annular plates. 
     
     
       4. A fluid pressure reduction device as defined in claim  2  wherein said axial flow path is located radially outwardly of the hollow center of said stack of annular plates. 
     
     
       5. A fluid pressure reduction device as defined in claim  1  wherein said pressure reduction flow path is defined by a plurality of pressure reduction stages in series and includes radial and axial flow components which alternate between adjacent plates in said stack of annular plates. 
     
     
       6. A fluid pressure reduction device as defined in claim  1  wherein said pressure reduction flow path is defined by a plurality of pressure reduction stages in series and includes radial and axial flow components through successive plates in said stack of annular plates, and wherein the number of annular plates defining said pressure reduction flow path is equal to the number of pressure reduction stages in said pressure reduction flow path. 
     
     
       7. A fluid pressure reduction device as defined in claim  1  wherein said pressure reduction flow path is defined by identical annular plates rotated relative to each other. 
     
     
       8. A fluid pressure reduction device as defined in claim  1  wherein said pressure reduction flow path is defined by two or more non-identical annular plates. 
     
     
       9. A fluid pressure reduction device as defined in claim  1  wherein the number of orifices discharging into the communication passage increases along said pressure reduction flow path. 
     
     
       10. A fluid pressure reduction device as defined in claim  1  wherein the flow areas of said orifices increase along said pressure reduction flow path. 
     
     
       11. A fluid pressure reduction device as defined in claim  1  wherein said annular plates define a plurality of pressure reduction flow paths in parallel between said first perimeter and said second perimeter. 
     
     
       12. A fluid pressure reduction device as defined in claim  1  wherein said communication passage has a width that is at least 3.5 times the width of said orifice. 
     
     
       13. A fluid pressure reduction device as defined in claim  1  wherein each pressure reduction stage is characterized by a velocity head loss greater than 75%. 
     
     
       14. A fluid pressure reduction device as defined in claim  1  wherein each pressure reduction stage is characterized by a pressure recovery less than 25%. 
     
     
       15. A fluid pressure reduction device as defined in claim  1  wherein said pressure reduction flow path includes alternating radial and axial flow components and wherein said axial flow components have one direction. 
     
     
       16. A fluid pressure reduction device as defined in claim  1  wherein said pressure reduction flow path includes alternating radial and axial flow components and wherein successive axial flow components have opposite axial directions. 
     
     
       17. A fluid control valve comprising: 
       a valve body having a fluid passageway;  
       a valve seat in said fluid passageway;  
       a valve plug that is movable with respect to said valve seat for controlling the flow of fluid through said fluid passageway; and  
       a fluid pressure reduction device mounted in said fluid passageway for reducing fluid pressure, said pressure reduction device comprising:  
       a stack of annular plates having a hollow center through which said valve plug is movable, a fluid inlet at a first perimeter thereof and a fluid outlet at a second perimeter thereof;  
       selected ones of said plates each defining at least one pressure reduction stage comprising an orifice having a well-rounded or well-tapered inlet and an abrupt discharge, said orifice having walls which do not diverge in a downstream direction between said inlet and said abrupt discharge, and a communication passage coupled to said discharge; and  
       each pressure reduction stage communicating with another pressure reduction stage in an adjacent one of said annular plates in said stack, two or more of said pressure reduction stages being coupled in series to define a pressure reduction flow path from said fluid inlet to said fluid outlet.  
     
     
       18. A fluid control valve as defined in claim  17  wherein said annular plates define at least one axial flow path through said stack for gradual reduction of fluid pressure at different axial levels in said stack of annular plates. 
     
     
       19. A fluid control valve as defined in claim  18  wherein said axial flow path opens onto the hollow center of said stack of annular plates for gradual reduction of fluid pressure between said annular plates and said movable plug at different axial levels in said stack of annular plates. 
     
     
       20. A fluid control valve as defined in claim  18  wherein said axial flow path is located radially outwardly of the hollow center of said stack of annular plates. 
     
     
       21. A fluid control valve as defined in claim  17  wherein said pressure reduction flow path is defined by a plurality of pressure reduction stages in series and includes radial and axial flow components which alternate between adjacent plates in said stack of annular plates. 
     
     
       22. A fluid control valve as defined in claim  17  wherein said pressure reduction flow path is defined by a plurality of pressure reduction stages in series and includes radial and axial flow components through successive plates in said stack of annular plates, and wherein the number of annular plates defining said pressure reduction flow path is equal to the number of pressure reduction stages in said pressure reduction flow path. 
     
     
       23. A fluid control valve as defined in claim  17  wherein said pressure reduction flow path is defined by identical annular plates rotated relative to each other. 
     
     
       24. A fluid control valve as defined in claim  17  wherein said pressure reduction flow path is defined by two or more non-identical annular plates. 
     
     
       25. A fluid control valve as defined in claim  17  wherein the number of orifices discharging into the communication passage increases along said pressure reduction flow path. 
     
     
       26. A fluid control valve as defined in claim  17  wherein the flow areas of said orifices increase along said pressure reduction flow path. 
     
     
       27. A fluid control valve as defined in claim  17  wherein said annular plates define a plurality of pressure reduction flow paths between said first perimeter and said second perimeter. 
     
     
       28. A fluid control valve as defined in claim  17  wherein said communication passage has a width that is at least 3.5 times the width of said orifice. 
     
     
       29. A fluid control valve as defined in claim  17  wherein each pressure reduction stage is characterized by a velocity head loss greater than 75%. 
     
     
       30. A fluid control valve as defined in claim  17  wherein each pressure reduction stage is characterized by a pressure recovery less than 25%. 
     
     
       31. A fluid control valve as defined in claim  17  wherein said pressure reduction flow path includes alternating radial and axial flow components and wherein said axial flow components have one direction. 
     
     
       32. A fluid control valve as defined in claim  17  wherein said pressure reduction flow path includes alternating radial and axial flow components and wherein successive axial flow components have opposite axial directions. 
     
     
       33. A fluid control valve as defined in claim  17  wherein said first perimeter is an inner perimeter of said stack of annular plates adjacent to said valve plug and said second perimeter is an outer perimeter of said stack of annular plates. 
     
     
       34. A fluid pressure reduction device comprising: 
       a stack of annular plates having a hollow center, a fluid inlet at a first perimeter thereof and a fluid outlet at a second perimeter thereof;  
       selected ones of said plates each defining at least one pressure reduction stage comprising an orifice having a well-rounded or well-tapered inlet and an abrupt discharge, and a communication passage coupled to said discharge, wherein each pressure reduction stage is characterized by a pressure recovery less than 25%; and  
       each pressure reduction stage communicating with another pressure reduction stage in an adjacent one of the annular plates in said stack, two or more of said pressure reduction stages being coupled in series to define a pressure reduction flow path from said fluid inlet to said fluid outlet.  
     
     
       35. A fluid pressure reduction device comprising: 
       a stack of annular plates having a hollow center, a fluid inlet at a first perimeter thereof and a fluid outlet at a second perimeter thereof;  
       selected ones of said plates each defining at least one pressure reduction stage comprising an orifice having a well-rounded or well-tapered inlet and an abrupt discharge, and a communication passage coupled to said discharge, wherein each pressure reduction stage is characterized by a velocity head loss greater than 75%; and  
       each pressure reduction stage communicating with another pressure reduction stage in an adjacent one of the annular plates in said stack, two or more of said pressure reduction stages being coupled in series to define a pressure reduction flow path from said fluid inlet to said fluid outlet.  
     
     
       36. A fluid pressure reduction device comprising: 
       a stack of annular plates having a hollow center, a fluid inlet at a first perimeter thereof and a fluid outlet at a second perimeter thereof;  
       selected ones of said plates each defining at least one pressure reduction stage comprising an orifice having a well-rounded or well-tapered inlet and an abrupt discharge, said orifice having walls which do not diverge in a downstream direction between said inlet and said abrupt discharge, and a communication passage coupled to said discharge;  
       each pressure reduction stage communicating with another pressure reduction stage in an adjacent one of the annular plates in said stack, two or more of said pressure reduction stages being coupled in series to define a pressure reduction flow path from said fluid inlet to said fluid outlet; and  
       said annular plates defining at least one axial flow path through said stack for gradual reduction of fluid pressure at different axial levels in said stack of annular plates.  
     
     
       37. A fluid pressure reduction device comprising: 
       a stack of annular plates having a hollow center, a fluid inlet at a first perimeter thereof and a fluid outlet at a second perimeter thereof;  
       selected ones of said plates each defining at least one pressure reduction stage comprising an orifice having a well-rounded or well-tapered inlet and an abrupt discharge, said orifice having walls which do not diverge in a downstream direction between said inlet and said abrupt discharge, and a communication passage coupled to said discharge; and  
       each pressure reduction stage communicating with another pressure reduction stage in an adjacent one of the annular plates in said stack, two or more of said pressure reduction stages being coupled in series to define a pressure reduction flow path from said fluid inlet to said fluid outlet, wherein said pressure reduction flow path includes radial and axial flow components which alternate between two adjacent plates in said stack of annular plates.  
     
     
       38. A fluid pressure reduction device comprising: 
       a stack of annular plates having a hollow center, a fluid inlet at a first perimeter thereof and a fluid outlet at a second perimeter thereof;  
       selected ones of said plates each defining at least one pressure reduction stage comprising an orifice having a well-rounded or well-tapered inlet and an abrupt discharge, said orifice having walls which do not diverge in a downstream direction between said inlet and said abrupt discharge, and a communication passage coupled to said discharge; and  
       each pressure reduction stage communicating with another pressure reduction stage in an adjacent one of the annular plates in said stack, two or more of said pressure reduction stages being coupled in series to define a pressure reduction flow path from said fluid inlet to said fluid outlet, wherein said pressure reduction flow path includes radial and axial flow components through successive plates in said stack of annular plates and wherein the number of annular plates defining said pressure reduction flow path is equal to the number of pressure reduction stages in said pressure reduction flow path.  
     
     
       39. A fluid pressure reduction device comprising: 
       a stack of annular plates having a hollow center, a fluid inlet at a first perimeter thereof and a fluid outlet at a second perimeter thereof;  
       selected ones of said plates each defining at least one pressure reduction stage comprising an orifice having a well-rounded or well-tapered inlet and an abrupt discharge, and a communication passage coupled to said discharge and having a width that is at least 3.5 times the width of said orifice; and  
       each pressure reduction stage communicating with another pressure reduction stage in an adjacent one of the annular plates in said stack, two or more of said pressure reduction stages being coupled in series to define a pressure reduction flow path from said fluid inlet to said fluid outlet.